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{{Short description|Meeting point of uplands and coastal plain}}{{About|the concept in geomorphology|fall line as a gradient|Fall line (topography)|other uses|Fall line (disambiguation)}}A fall line (or fall zone) is the area where an upland region and a coastal plain meet and is noticeable especially where rivers cross it, with resulting rapids or waterfalls. The uplands are relatively hard crystalline basement rock, and the coastal plain is softer sedimentary rock.BOOK, Schneider, Craig W., Richard B. Searles, Seaweeds of the southeastern United States: Cape Hatteras to Cape Canaveral, 1991, Duke University Press, 978-0-8223-1101-0, 5–7,weblink 17 November 2010, A fall line often will recede upstream as a river cuts out the uphill dense material, forming "c"-shaped waterfalls and exposing bedrock shoals. Because of these features, riverboats typically cannot travel any farther inland without portaging, unless locks are built. The rapid change of elevation of the water and resulting energy release make the fall line a good location for water mills, grist mills, and sawmills. Seeking a head of navigation with a ready supply of water power, people have long made settlements where rivers cross a fall line.

Geography

File:Bulletin 426 Fig 2 Fall Line.jpg|thumb|right|300px|Diagram showing the Fall Line. USGSUSGSThe slope of rivers crossing fall zones affected settlement patterns. For example, the fall line represents the inland limit of navigation of many rivers. As such, many cities along a fall line grew as a result of demand for transferring people and goods between land-based and water-based transportation at that place.WEB,weblink The Fall Line and major cities of the Eastern U.S., {{Globalize|section|USA|2name=the United States|date=November 2016}}

North American Atlantic Seaboard Fall Line

{{GeoGroupTemplate|align=left}}The Atlantic Seaboard Fall Line, or Fall Zone, is a {{convert|900|mi|km|adj=on|abbr=off|order=flip}} escarpment where the Piedmont and Atlantic Coastal Plain meet in the eastern United States.BOOK, Freitag, Bob, Susan Bolton, Frank Westerlund, Julie Clark, Floodplain Management: A New Approach for a New Era, 2009, Island Press, 978-1-59726-635-2, 77,weblink 17 November 2010, Much of the Atlantic Seaboard fall line passes through areas where no evidence of faulting is present.The fall line marks the geologic boundary of hard metamorphosed terrain—- the product of the Taconic orogeny—- and the sandy, relatively flat outwash plain of the upper continental shelf, formed of unconsolidated Cretaceous and Tertiary sediments. Examples of the Fall Zone include the Potomac River's Little Falls and the rapids in Richmond, Virginia, where the James River falls across a series of rapids down to the tidal estuary of the James River. Columbia, South Carolina, is similar as well with the Congaree River.Before navigation improvements such as locks, the fall line was often the (wikt:head of navigation|head of navigation) of rivers due to rapids and waterfalls, such as the Little Falls of the Potomac River. Numerous cities were founded at the intersection of rivers and the fall line. U.S. Route 1 links many of the fall line cities.In the USA, Mid-Atlantic and Southern fall line cities include:

• Paterson, New Jersey, on the Passaic River{{Citation needed|date=January 2017}}
• Trenton, New Jersey, on the Delaware River
• Philadelphia, Pennsylvania, on the Schuylkill RiverBOOK, Shamsi, Nayyar, Encyclopaedia of Political Geography, 2006, Anmol Publications, 978-81-261-2406-0, 92–93,weblink 17 November 2010, BOOK, Dunkerly, Robert, Boland, Irene, Eutaw Springs, 2017, The University of South Carolina Press, Columbia, 9781611177589, 24,
• Wilmington, Delaware, on Brandywine CreekWEB,weblink A Summary of the Geologic History of Delaware, The Delaware Geological Survey, 25 January 2017,
• Baltimore, Maryland, on the Jones Falls, Gunpowder Falls and Gwynns FallsWEB,weblink Maryland Geology, Maryland Geological Society, 25 January 2017,
• Washington, D.C., on the Potomac RiverWEB,weblink Geology of the Fall Line, Virginia Places, 25 January 2017,
• Fredericksburg, Virginia, on the Rappahannock River
• Hanover, Virginia, on the North Anna River{{Citation needed|date=January 2017}}
• Richmond, Virginia, on the James River
• Petersburg, Virginia, on the Appomattox River
• Weldon, North Carolina, and Roanoke Rapids, North Carolina, on the Roanoke RiverWEB,weblink Fall Line, NCpedia, 25 January 2017,
• Rocky Mount, North Carolina, on the Tar River
• Raleigh, North Carolina, on the Neuse River
• Fayetteville, North Carolina, on the Cape Fear River
• Camden, South Carolina, on the Wateree River
• Columbia, South Carolina, on the Congaree River
• Augusta, Georgia, on the Savannah RiverWEB,weblink Fall Line, The New Georgia Encyclopedia, 17 October 2011,
• Milledgeville, Georgia, on the Oconee River
• Macon, Georgia, on the Ocmulgee River
• Columbus, Georgia, on the Chattahoochee River
• Tallassee, Alabama, on the Tallapoosa RiverWEB,weblink Fall Line, Encyclopedia of Alabama, 25 January 2017,
• Wetumpka, Alabama, on the Coosa River
• Tuscaloosa, Alabama, on the Black Warrior River

Canada

The Laurentian Upland forms a long scarp line where it meets the Great Lakes–St. Lawrence Lowlands. Along this line numerous rivers have carved falls and canyons (listed east to west):

• Saint Anne Falls and Canyon Sainte-Anne (River Sainte-Anne-du-Nord)
• Chaudron à Gaudreault (Rivière aux Chiens)
• Unnamed falls (Rivière du Sault à la Puce)
• Canyon of the River Cazeau
• Montmorency Falls (River Montmorency)
• Kabir Kouba Fall (River Saint-Charles)
• Chute Ford (River Sainte-Anne)
• Sainte-Ursule Falls (River Maskinongé)
• Chute à Magnan (Rivière du Loup)
• Chutes Émery and Chute du Moulin Coutu (Rivière Bayonne)
• Les sept chutes (River de L'Assomption)
• Dorwin Falls (River Ouareau)
• Wilson Falls (Rivière du Nord)
• Long Sault, now flooded by the Carillon hydroelectric generating station (Ottawa River)
  • The Chaudière Falls run over the unrelated Eardley Escarpment of the Ottawa-Bonnechere Graben.

The River Jacques-Cartier and River Saint-Maurice lack such noticeable feature because they cross the scarp through U-shaped valleys. The falls of the lower Saint-Maurice (as well as those of the River Beauport, in Quebec City) are due to the fluvial terraces of the Saint Lawrence river rather than the Laurentian Scarp.

See also

• Geologic map of Georgia (U.S. state)
• Spring line settlement

References

{{Reflist}}

External links

• EB1911, Fall-line, x,

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